Management, Impact and Economics of Beef Cattle Grazing in Mountain Riparian Ecosystems

Objective 1. Integrate cattle grazing methods and physical factors of mountain riparian ecosystems into a ranching model that demonstrates sustainable natural resource use.

In 1996 and 1997 our research team took an interdisciplinary approach in examining how off-stream water and salting affected the distribution of cattle in the mountainous regions of the West. The findings and methods in that study have been peer reviewed by both academia and agency professionals. The ensuing feedback and commentary have been a key component in refining our further examination of cattle distribution. A diverse team of researchers with various backgrounds along with two new graduate students carried out the second phase of the grazing project under the SARE funding.

Our focus for this two-year study was the examination of seasonal grazing on riparian pastures. We were looking to see if the timing of grazing could be used as a management tool to enhance riparian health, while simultaneously benefiting ranching as a way of life in the West. To accomplish this, scientists and graduate students from Oregon State University and University of Idaho’s Agricultural Experiment Station and Extension Service and the Pacific Northwest Research Station (USDA, Forest Service) organized to take an interdisciplinary approach to this perplexing and contentious issue.

Using Oregon State University’s Hall Ranch in Union, Oregon, our team developed and implemented a study design that simulates a Western ranching operation. A randomized three-block design of nine pastures was created, with each pasture containing a riparian habitat and its associated stream segment. We elected to analyze early spring and late summer grazing periods. In each period, three of the nine pastures were grazed for 28 days at moderate stocking levels. The three remaining pastures were used as ungrazed controls. A number of environmental and animal characteristics were measured before and after each grazing period to assess any change in riparian health and/or beef production attributed to our management practices.

The Eastern Oregon Agricultural Research Center’s Hall Ranch of Oregon State University serves as the study site. The Hall Ranch is located in the Cathrine Creek drainage northeast of Union, Oregon, which is spawning habitat for migrating salmon. A salmon-rearing stream (Milk Creek) runs lengthwise through the demonstration/research site and drains into Cathrine Creek. This study site ranges in elevation from 4100 to 4900 feet. Soils originate from two dominant parent materials: 1) silt-sized volcanic ash originating from Mount Mazama eruptions and 2) basalt. Vegetation groups are grand fir (abies grandis) forest on the north slopes, mixed conifer forest, wet meadow, and riparian. Dominant plant species are grand fir, douglas fir (Psudotsuga menziesii), ponderosa pine (Pinus ponderosa), ninebark (Physocarpus malvaceus), ocean spray (Holodisus discolor), snowberry (Symphoricarpos albus), pine grass (Calamagrostis rubescens), elk sedge (Cares geyeri), and Kentucky bluegrass (poa pratensis). Fall and spring environments typically are cool and moist, while summers are hot and dry. Precipitation averages 66 centimeters annually with 60% occurring during the winter period. Snow is common and may be continuous in winter with accumulations in excess of one meter possible. Temperatures commonly range from -18°C (winter) to 38°C (summer).

During each grazing period, 8 days of intensive observations were conducted to continuously monitor cattle distribution cycles and foraging behavior. This was attained through hourly field recordings on each animal’s location within each pasture and was accompanied by data gathered from continual feeding recorders (vibracorders) worn by the animals. In order to estimate any changes in cattle production, each animal was weighed and body condition scored before and after each grazing period. With these data and collected forage quality samples, we can observe the linkages between changing production levels, cattle distribution, and seasonal forage availability.

The researchers found that as the grazing season progressed along with increased daytime temperatures and decreased forage quality, the average livestock distance from the stream decreased (Figure 2). The cattle grazing riparian areas later in the summer spent a greater portion of the day loafing near the stream accompanied with a greater number of fecal deposits within 1 meter of the stream (a measure of livestock concentration or density). Under certain conditions this could result in riparian area degradation due to increased utilization of riparian forages, bank trampling and greater woody vegetation use.

On the positive side, results from this study indicate that early summer grazing of riparian areas has decreased impacts on riparian areas due to improved livestock distribution and less time loafing near the stream. The increase in distribution is most likely due to lower daytime temperatures (Figure 3) along with higher moisture content of the early season forage (Table 1).

Implementation of early summer grazing of riparian areas into a grazing management system has proved to be very effective in altering the duration, distribution, and vegetation utilization patterns of cattle grazing a riparian area and its adjacent uplands along the foothills of the Wallowa Mountains (Figures 4 and 5). During early summer, when forage quantity and composition are not limiting and ambient air temperatures are low, livestock distribution patterns are more evenly distributed and vegetation utilization patterns are more uniform (Table 2). During late summer, ambient air temperatures increase, forage DM increases, livestock distance from the stream decreases, and fecal deposits within 1 m of the stream increase (Table 3). These factors, in turn, may lead to increased riparian area vegetation utilization and woody browse, and increased bank trampling. As long as early use does not cause problems due to wet saturated soils, early summer grazing of riparian areas may be less detrimental to riparian areas due to improved livestock distribution and more uniform vegetation use.

Based on these observations, managers may make better management decisions using factors like off-stream water sources, herding of cattle during the heat of the day, and providing alternative shade sources for cattle during the late summer grazing period. These actions may achieve more uniform cattle distribution and vegetation utilization patterns. While these are potential management alternatives, management must remain aware of the forces in a particular system that are driving livestock distribution patterns and implement decisions accordingly. Factors such as shade, time of day, time of year, location and availability of water, temperature, vegetation types, and forage quality and quantity, or a combination of these factors, influence livestock distribution patterns and subsequent vegetation utilization patterns.

Rangelands and riparian areas are dynamic systems and are constantly changing, thus making management decisions a daily activity. This variability necessitates the need for adaptive management aimed at meeting environmental goals, while still achieving ranch or management economic goals. Continued, focused research is needed in order to obtain a better understanding of the dynamics and interactions of these variable and ever changing riparian systems.
This research group expects to combine these results with previous studies to design compatible grazing systems that will allow sustained use of these important natural resources.

Technical publications are included in the appendices of this report along with other citations and reprints which are available upon request.

Objective 2. Conduct range and riparian monitoring and bioassessments of mountain riparian ecosystems to determine the impacts of livestock grazing.

Environmental assessment of alternative grazing periods included greenline, geomorphology, and macroinvertebrate variables, analyzed separately and in an integrated fashion. Data collection was undertaken between June and September 1998 and 1999.

Researchers have employed a series of new techniques for improved stream assessment and monitoring. We have made an effort to capture the system dynamics that are naturally inherent in our study design, so that we may speak more confidently about our observations. Our graduate students have tailored their programs of study to match our project needs and reviewed numerous literature in this field. They have applied new advancements in stream monitoring and water quality analysis to our study. Some of this year’s initial raw data have even been presented to a number of university specialists in various fields by our graduates, so they can skillfully convey its information in their final analysis. These improvements, along with others, will allow us to gain a better understanding of how cattle impact surface water quality and influence changes in aquatic populations.

Greenline vegetation is defined as the first perennial vegetation above the stable low water line of a stream or water body. The composition, distribution, amount, and ecological condition of greenline vegetation influences sediment capture, erosion, streambank stability, water quality, and habitat for aquatic and riparian organisms. Removal of greenline vegetation or mechanical bank damage reduces the structural stability of the stream channel. The purpose of this study was to compare the impacts of early season (June-July) and late season (August-September) grazing on greenline vegetation and stream bank stability.

Streambank stability and cover was measured following protocol of EPA (1993). Streambank stability (“stable” and “unstable”), and streambank cover (“covered” and “uncovered”) was measured to the nearest 0.5 m along each side of Milk Creek within each treatment pasture before and after each grazing period. “Unstable” banks were further partitioned into four categories: (a) “breakdown” if there were obvious blocks of banks broken away and lying in the creek adjacent to bank breakage; (b) “slumping” if the bank had obviously slipped down; (c) “fracture” if a crack was visible on the bank indicating the block was about to slump or break off into the stream; and (d) “vertical and eroding” if the bank angle was steeper than 80 degrees from the horizontal. When none of these conditions were observed, the bank was classified as “stable.”

Streambanks were also classified as “covered” or “uncovered.” A “covered” streambank showed any of the following conditions: (a) perennial vegetation ground cover was greater that 50%; (b) roots of vegetation covered more than 50% of the bank; (c) at least 50% of the bank surface was protected by rocks of cobble-size or larger; and (d) at least 50% of the bank surface was protected by logs four inches in diameter or larger. When none of these criteria were met the bank was classified “uncovered.”

Data from the late-season grazing period (August-September) are being compiled and summarized. Data from early-season (June-July) grazing are summarized below. The proportion of greenline impacted by livestock (defined as the presence of hoof prints) following early-season grazing was 33.6%, 20.9% and 33.4%, for blocks 1, 2 and 3, respectively. Cattle-impacted greenline was further grouped into four classes (Table 4).

Greenline vegetation cover and bank stability classes were combined to form the following groups: (1) “non-erosional” was considered to be “covered” and “stable”; (2) “vulnerable” was either “uncovered” and “stable” or “covered” and “unstable”; and (3) an “erosional” category was assigned to “uncovered” and “unstable” greenline. Tables 5 and 6 show the proportion of each category before and after early-season grazing.

For the third consecutive year the extent to which different cattle management systems influence moth species diversity and abundance was conducted. Moths are an important component of biodiversity in most terrestrial systems – they are one of the most abundant groups of herbivores of various species of plants, serve as an important food source for many vertebrate predators, and perform some pollination services. Over 375 species of moths within the treatment units at the Hall ranch study site have been collected, which makes up over 60% of the total species in the Blue Mountain area. Significant effects for a number of species in terms of habitat (upland vs. riparian) and season (May through September) have been detected but no systematic patterns of treatment effect (late vs. early turnout of cattle) were determined.

During the field season of 1998, the fitness of individual caddis fly pupae (Glossosoma) was studied to determine the effects of season, habitat and cattle grazing treatment. This species of caddis fly is an algae grazer and is a relatively sensitive indicator of changes in water quality, being typically found in fairly pristine stream systems. Weight of individual caddis flies is reflective of its fitness, and in female will influence egg production. Results so far indicate a strong difference in habitat for caddis fly pupal weight, with sunny stream segments being more favorable. Cattle grazing practices did not effect pupal weights.

Bioassessment: Stream bank cover and stability

Inappropriate cattle management can contribute to declines in riparian community stability by removing protective vegetation and increasing bank instability through trampling. The purpose of this portion of the study is to compare grazing treatment effects on greenline vegetation and bank stability.

Measurements of streambank cover and stability followed protocol of Platts et al. (1983) as modified by Bauer and Burton (1993). Streambank cover (rated either “covered” or “uncovered”) and stream bank stability (rated either “stable” or “unstable”) was measured by pacing each side of Milk Creek and recording the appropriate cover and stability class within plots defined lengthwise as a step (0.5 m) taken parallel to the stream. Plot width was defined as the vegetative greenline located below the bankful level but above the scour line (Bauer and Burton 1993). Number of plots of the various cover/stability classes were tallied and converted to m/100 m of streambank. Additionally, each plot was examined for the presence of hoof prints. When one or more was found, the plot was recorded as “cattle present.” Measurements were taken within each treatment before and after cattle grazing.

Streambanks were considered covered if they contained any of the following features: perennial vegetation ground cover greater than 50%; roots of deeply rooted vegetation such as shrubs or sedges covered more than 50% of the bank; at least 50% of the bank surface protected by rocks of cobble size or larger; and at least 50% of the bank surface protected by logs of four inches diameter or larger (Bauer and Burton 1993). Otherwise banks were rated “uncovered.” Banks within each plot were rated “stable” unless they exhibited any of these features: blocks of bank broken away and lying adjacent to the bank breakage; bank sloughed into stream channel; bank cracked and about to move into stream. Otherwise, banks were rated “unstable.” Observed plots will be grouped into four classes: covered/stable; covered/unstable; uncovered/stable; and uncovered/unstable.

Objective 3. Determine economic implications of alternative grazing management to improve the ecological condition of riparian areas.

The graduate student at Oregon State University is completing his Master’s thesis to evaluate the economic benefits and costs associated with the seasonal use of riparian pastures and off-stream water and salting. This student is developing a method to evaluate these two grazing “Best Management Practices” at the ranch level. He has met with local farm and resource agencies to discuss our study, and has found that both ranchers and agency personnel are seeking economic information upon which to base ranching decisions in light of increasing public pressure for agricultural conservation measures. His goal is to provide a readily available, comprehensible publication that ranch managers and government agencies can look to for information upon which to base their management strategies.

In the Classroom

This project has provided a unique opportunity for our graduate students. The students assigned to this study were able to utilize their summer fieldwork in class reports, presentations, and analytical exercises. This increased exposure of our project to other trained academics and professionals has refined a number of our data collection and analytic techniques. Through discussion and critique, our study has not only improved its procedures, but it has also enriched the classroom experience of graduates studying at both the University of Idaho and Oregon State University. Our attention to environmental assessment has benefited the most through this broadened peer exposure.

Presentations

Work on the project was presented at Oregon State University’s 1999 Annual Graduate Student Conference. The Graduate Student Association of Oregon State sponsors a university-wide conference, showcasing the diverse research of OSU graduate students. Jeff Sharp presented our work in a special session of the program titled “It Takes a Village to Raise a Fish,” which highlighted multidisciplinary research addressing issues of Oregon’s declining anadromous fish populations. Our findings on the economic feasibility of our project was presented at the Society for Range Management 2000 Annual Meeting in Boise, Idaho.

Refined Photographic Documentation

We have greatly improved upon the photo documentation of our grazing management. Over a hundred photos were systematically taken to record before and after conditions of each grazed pasture. Many of the images illustrate a dramatic difference in forage composition before and after each grazing period. The digitized images will be useful in future media presentations of this project.

Improved Sampling and Data Collection Methods

Early presentation and discussion of our environmental assessment methods to our peers in the classroom and one-on-one has prompted us to refine our sampling and data collection procedures. We expanded our water quality sampling methods to include a procedure that will examine the variability of our fecal coliform collection practices. We also employed the use of a digital velocity meter to more accurately calculate estimated stream flow. A detailed analysis of our water quality data was conducted, however initial analysis suggests that grazing cattle along riparian corridors early in the season has less of a net effect on water quality. The difference between seasons is slight and varies with each parameter analyzed and year measured. Further analysis of the data is warranted. Table 7 provides a simple synopsis of how each grazing season influenced each water quality parameter.

In order to understand how temperature influences our cattle’s distribution, we employed the use of continuous recording temperature loggers into our data collection procedures. We utilized four temperature loggers; one in the riparian area, one in the open meadow, one in the upland trees, and one placed directly into the creek. The recorded data will be used to illustrate how cattle distribute themselves from the stream with a rise and fall in ambient air temperature.

Integration of Modeling and Data Analysis

In recent years our group has focused our research on methods to improve cattle distribution in riparian pastures. A mathematical programming model has been developed by one of our students that will integrate our work over the past four years. A bio-economic model will simultaneously analyze the long-term economic feasibility of seasonal grazing and off-stream water development in the riparian zone. The model will be asked to choose the most appropriate management strategy under various natural and economic conditions.